Ellie Murray and Lucy D'Agostino McGowan chat about ecological studies, the new Pfizer vaccine interim analysis, and more! ? Vanderbilt University Department of Health Policy's COVID-19 Deaths in Tennessee and Adoption of Mask Requirements (h/t Peter Rebeiro)  ? The original masks v no masks graph ? Pfizer's press release about the interim analysis for their vaccine trial ? Pfizer's vaccine trial protocol PeDAGogy Here is the DAG from our peDAGogy segment: Follow along on Twitter: The American Journal of Epidemiology: @AmJEpi Ellie: @EpiEllie Lucy: @LucyStats ? Our intro/outro music is courtesy of Joseph McDade. ?‍? Our artwork is by Allison Horst.